Procter and Gamble""s U.S. Pat. No. 5,234,617 mentions the use of enzymes as a desirable component in liquid compositions combined with peroxyacids. The use of enzymes is also mentioned as an optional component of sequestrants in order to prevent the loss of available oxygen, since they sequester heavy metal ions, such as magnesium, calcium, aluminum, etc.
Procter and Gamble""s U.S. Pat. No. 5,559,089 mentions the use of a peroxide bleaching agent and indicates its compatibility with various types of enzymes, applied in powder form for the automatic washing of dishes. The sequestrant agents are described in various patents, including U.S. Pat. No. 3,442,937 of Sennewald, U.S. Pat. No. 2,838,459 of Sprout, Jr. and U.S. Pat. No. 3,192,255 of Carn. In addition, the use of a peroxide bleaching agent is mentioned in U.S. Pat. No. 4,299,716 of Lever Brothers Company.
The peroxyacids used in the above-mentioned patents include 4-nonylamine-4-oxoperoxybutyric acid, heptylsulfonylperpropionic acid, decyl-sulfonylperbutyric acid and others. However, the enzymes that are optionally combined with sequestrants have not previously been considered as perborate stabilizers in their various forms of hydration. Thus, although other patents mention the use of chelates, these are used as enzyme stabilizers, such as in U.S. Pat. No. 4,318,818 of Procter and Gamble.
The latest research of enzyme-producing companies indicates that their encapsulated enzymes notably increase the washing efficiency of those cleaning products that contain peroxide bleaching agents in their formula.
The Clorox Company""s U.S. Pat. No. 5,255,102 indicates that once covered or encapsulated, enzymes do not undergo any kind of denaturalization in powder compositions containing oxidant bleaching agents, such as peroxyacids.
Nevertheless, it is not until now, as a result of several tests and experiments that we have conducted, that a detergent composition in solid form and containing surfactant, a peroxide bleaching agent and enzymes has been developed. Its process is also innovative and has been shown to reduce deactivation and maintain the stability of the peroxide bleaching agent and enzyme in the composition""s solid matrix.
The invention describes a detergent composition in solid form containing surfactant and a peroxide bleaching agent. In another preferred composition, encapsulated or non-encapsulated enzymes may be present, improving the washing performance of the product. Because the solid matrix of the composition reaches a free environmental humidity equal to or less than 6%, excellent cleaning results were obtained from the sodium perborate monohydrate, without bleaching agent activators, and from the enzyme, under hand washing conditions using water at temperatures under 55 degrees Centigrade. Other conventional additives, such as sequestrants, systems for strengthening detergency, some alkaline salts, skin conditioners, perfumes, coloring agents, fillers, anti-redeposition agents, fabric softeners, etc., may be optionally present.
The composition is suitable for hand washing and soaking of clothes. The process for the formulation of this composition is also fundamental in order to attain the stability of the peroxide bleaching agents and the enzyme. For this reason, hydrating salts and materials with low moisture levels are used.